Compress video for Slack
Slack allows files up to 1 GB on every plan — but a lean recording uploads in seconds and previews instantly. Compressed on your device.
Drop your video here
or
MP4, MOV, WebM, MKV, AVI and more — any size, no upload
🔒 Files never leave your device — everything runs in your browser.
Slack has exactly one per-file rule: uploads up to 1 GB, on free and paid plans alike. What differs on the free plan is memory, not size — files older than 90 days drop out of view, and past a year they are deleted. So the real Slack problem is rarely the cap; it is the 600 MB screen recording that takes ages to upload, ages to download, and stutters in the inline player for everyone in the channel.
Compressing before you post fixes all three at once. A demo or bug recording shrunk to a tenth of its size uploads before you finish typing the message, and teammates on laptops and phones scrub through it instantly. Everything runs on your own device — a work recording never touches a third-party server on its way into your workspace.
How it works
- Drop your file
Any common format, any size. Nothing is uploaded — the tool runs in your browser.
- Pick your target
Use the presets above — this page's defaults are tuned for compress video for slack — or type any size.
- Download
Your converted file is ready on your device — nothing to wait for, nothing to delete from a server.
Frequently asked questions
What is Slack's file size limit right now?
1 GB per file, on every plan — free and paid change message history and retention, never the upload cap. Anything over 1 GB is rejected no matter who you are.
Why compress if the cap is a whole gigabyte?
Because everyone downstream pays for the bytes: big uploads crawl on office Wi-Fi, the inline player buffers, and phones choke on gigabyte files. A compressed recording behaves like a screenshot — instant to post, instant to watch.
Do files disappear on the free plan?
They leave view after 90 days and are permanently deleted after one year on free workspaces — a retention rule, not a size rule. If a recording matters long-term, keep the original somewhere you control; Slack's copy is temporary on the free plan.
Is my file uploaded to a server?
No. ConvertUno runs entirely in your browser on your own device. Your file never leaves your computer or phone — there is no upload at all.
Is it really free, with no watermark?
Yes. Processing happens on your device, so serving you costs us almost nothing — no watermark, no account, no file-size limit, no daily quota.